Device for humidifying an air stream

ABSTRACT

A device for conditioning room air and/or process air, having a nozzle system that has a plurality of nozzles arranged in one or more nozzle branches, for atomising liquid, and at least one pump by means of which the liquid being atomised is pressurised, wherein said nozzles are designed as swirl nozzles and/or the pump applies a pressure to the liquid being atomised of between 3 and 50 bar. The liquid, particularly water, can be atomised particularly finely and a good degree of evaporation can be achieved, as a result of which the amount of water loss is also reduced. The device has a low susceptibility to failure, a long pump service life and low maintenance requirements.

The invention relates to an apparatus for humidifying an air stream, having a nozzle system which has multiple nozzles for atomizing liquid, and having at least one pump, by means of which the liquid to be atomized is subjected to pressure, and to an installation for the treatment of workpieces.

DE 41 10 550 C2 describes a device for humidifying air with pressurized water, which consists of a supply container for the water, a housing which is situated thereabove and through which the air flows, a nozzle assembly arranged therein and a steplessly regulable pump which delivers the water to said nozzle assembly.

DE 42 291 72 C1 discloses an apparatus for humidifying an air stream of an air-handling facility, in particular a process air installation or room air installation, having a spray nozzle arrangement for liquid atomization, in particular water atomization, which has multiple spray nozzles, which are arranged adjacent to one another with respect to the direction of air flow and are situated in the air flow.

It is an object of the present invention to provide an apparatus for air humidification which, with regard to its functionality, is improved in comparison with the prior art and is particularly suitable for industrial use.

Said object is achieved by an apparatus of the type mentioned in the introduction, wherein the nozzles are designed in the form of swirl nozzles and are arranged in one or more nozzle bars, and/or wherein the pump is designed such that the pressure of the liquid to be atomized is between 3 and 50 bar. In this way, fine atomization by the nozzles and/or a good degree of evaporation can be achieved. At the same time, the quantity of water lost can be reduced. The apparatus according to the invention is furthermore distinguished by low susceptibility to faults, a long service life of the pump and low maintenance effort. Moreover, the operating and investment costs for the apparatus according to the invention are relatively low, in particular in comparison with known air washers, high-pressure humidifiers or hybrid humidifiers.

Advantageously, the nozzles may be designed in the form of simplex nozzles. In this way, the robustness of the apparatus in relation to light water impurities and the suitability for industrial use can be further improved.

In an advantageous configuration, the nozzles may each have at least one filter apparatus, which is integrated into the nozzle. In this way, a compact design can be achieved and the robustness can be further increased.

Preferably, the pump may be designed in the form of a centrifugal pump. In this way, it is possible for the maintenance effort to be further reduced and for the pump service lives to be increased.

It may be expedient for the pump to be designed in the form of a reciprocating-piston pump.

Advantageously, the pressure provided by the pump may be between 20 and 50 bar. In this pressure range, it is possible to achieve relatively fine atomization of the liquid with advantageous operating costs.

The apparatus can be operated particularly favorably if the pressure provided by the pump is between 3 and 30 bar, preferably between 8 and 25. In this way, a favorable drop spectrum of the atomization can be achieved, wherein, in particular in the case of centrifugal pumps being used, the maintenance effort and the operating costs are relatively low and the pump service lives are relatively long.

The effectiveness of the humidification of the air stream can be further improved if the nozzles are arranged on a nozzle assembly which is equipped with turbulators.

It is particularly favorable for the humidification of the air stream if the turbulators are arranged upstream of the nozzles in the air stream.

Advantageously, the apparatus for humidifying the air stream may have at least one adjustment apparatus for setting the orientation of one or more nozzles of the nozzle system.

One solution which is particularly favorable with regard to different humidity requirements is provided if the nozzles of a first nozzle bar have a degree of atomization which differs from the degree of atomization of the nozzles of a second nozzle bar.

It may be expedient if nozzles which follow one another along a nozzle bar each have a different orientation.

Advantageously, a control apparatus may be provided, with the aid of which the supply of liquid to the nozzles is able to be regulated, for example via the regulation of the pump rotational speed. The atomization pressure and/or the volume flow may be set in a manner dependent on the pump rotational speed.

It is preferably possible for multiple nozzle bars to each be coupled to a valve apparatus, with the aid of which the supply of liquid to the corresponding nozzle bar is able to be regulated. In this way, the nozzle bars can be individually operated in a clocked manner and/or activated or deactivated, whereby a variable and particularly efficient operation of the apparatus is made possible.

One solution which is particularly favorable in terms of regulation is provided if provision is made of at least one sensor which is coupled to the control apparatus and which serves for measuring humidity in the air stream, preferably in the humidified air stream.

Further advantageous configurations of the invention will emerge from the following description. Here, exemplary embodiments of the invention will be discussed in more detail on the basis of the drawing without being restricted thereto. In the figures, in a simplified schematic illustration:

FIG. 1 shows the structure of an air-conditioning system in a basic illustration;

FIG. 2 shows a part of a nozzle assembly in a perspective view;

FIG. 3 shows a turbulator apparatus in a perspective view;

FIG. 4 shows a part of a nozzle assembly with a nozzle and with a turbulator apparatus in a sectional view;

FIG. 5 shows a side view of a nozzle with a spray cone;

FIG. 6 shows a side view of a nozzle, around which air flows, with a spray cone;

FIG. 7 shows a side view of a nozzle, around which air flows, with a spray cone and with a turbulator apparatus;

FIG. 8 shows a nozzle assembly with multiple nozzle bars in a perspective view;

FIG. 9 shows a nozzle assembly with multiple nozzle bars in a perspective view;

FIG. 10 shows a nozzle bar in a perspective view;

FIG. 11 shows a longitudinal section of a treatment facility for the treatment of vehicle bodies with a treatment tunnel which is supplied with conditioned process air by means of an air-supply device, said conditioned process air having been conditioned by means of a conditioning apparatus, wherein the conditioning apparatus comprises an air-conditioning system as per FIGS. 1 to 9.

FIG. 1 shows the basic structure of an air-conditioning system for conditioning room and/or process air, which comprises an apparatus for humidifying an air stream. The apparatus for humidifying an air stream is, as per the example shown, designed in the form of an air humidification device 4 having a reaction chamber 6 and having a control apparatus 48. The reaction chamber 6 has an inlet 92 and an outlet 94 for the air stream. The air stream to be conditioned is supplied to the air humidification device 4, as indicated by the arrow 10, on the side of the inlet 92 and flows through the reaction chamber 6 of the air humidication device 4 in the direction of the arrows 10, 12. In the reaction chamber 6, the air is conducted through a nozzle system 8 having multiple nozzles 14, wherein the nozzles are arranged in a so-called nozzle assembly 30. For the purpose of humidifying the air stream, a liquid, preferably water, is atomized by means of the nozzles 14, wherein the atomized liquid can be taken up by the air as moisture. On the side of the outlet 94, the conditioned air stream exits the air humidification device 4, as indicated by the arrow 12.

Water is supplied via supply lines 32 to the nozzles 14 arranged in the reaction chamber 6, wherein, by means of a pump 34, the water is subjected to pressure and is pumped from a water inflow 38 to the nozzles 14 of the nozzle system 8. It is possible to provide in the water inflow 38 a fine filter, for example for particles having a diameter of up to 10 μm. Preferably, the nozzle system 8 has multiple nozzle bars 28, wherein a nozzle bar 28 has in each case multiple nozzles 14. In the example shown, the nozzle bars 28 extend perpendicular to the plane of the drawing. One or more valve apparatuses 36 are provided between the pump 34 and the nozzles 14, wherein preferably, in each case one valve apparatus 36 is provided per nozzle bar 28. As per the example shown in FIG. 1, each nozzle bar 28 has a supply line 32 which is provided with a valve apparatus 36. A valve apparatus 36 may be designed for example in the form of a two/two-way valve. In the example shown, the pump 34 and the valve apparatuses 36 are coupled to the control apparatus 48. By means of the control apparatus 48, it is possible in particular for the supply of liquid to the nozzles 14 to be regulated.

The fact that the nozzles 14 are designed in the form of swirl nozzles, preferably in the form of simplex nozzles, means that the atomized liquid is able to form a very fine drop spectrum even at relatively low pressure. A relatively fine atomization can be achieved for example even starting from a pressure of approximately 3 bar. Ideally, the liquid to be atomized is subjected to a pressure in a range from approximately 3 bar to approximately 50 bar. Depending on the configuration of the pump and of the nozzle system 8, operation in a pressure range from approximately 20 bar to approximately 50 bar can be an advantage. Basically, the fineness of the atomized liquid spray and the evaporation, in particular of water, increase with increasing pressure. The use of swirl nozzles is particularly advantageous if the pump 34 is designed in the form of a centrifugal pump, preferably in the form of a multi-stage centrifugal pump. In the case of the use, described here, in an air humidication system 4, multi-stage centrifugal pumps are able to provide a pressure of up to approximately 45 bar. Accordingly, it can be an advantage if the liquid to be atomized is subjected to a pressure in a range from approximately 3 bar to approximately 30 bar, preferably between 8 bar and 25 bar. In a further configuration, it is possible to provide a reciprocating-piston pump as a pump 34 for the nozzle system 8 of the air humidification device 4.

In the example shown, a straightener 16 for the air stream is provided in the entry region of the air humidification device 4, that is to say in a manner arranged upstream of the nozzle system 8 in the direction of the air stream. If appropriate, such a straightener 16 may be dispensed with. Provided in the exit region of the air humidification device 4, that is in a manner arranged downstream of the nozzle system 8 in the direction of the air stream, is preferably a separating system 18, with the aid of which water not taken up by the air can be separated off. The separating system 18 may, for example, be of single- or two-stage design. In the example shown, the separating system 18 is of two-stage design and has an agglomerator 20 and a drop separator 22 which is arranged downstream of the agglomerator 20. The agglomerator 20 serves in particular for the separation and subsequent post-evaporation of fine drops from an aerosol. For this purpose, the agglomerator 20 may have for example at least one stainless steel mesh and/or plastic mesh, through which the air or the aerosol flows. If the agglomerator 20 is wetted with water, then it may also serve as a post-evaporator and reduce variations in the humidification of the air. For the purpose of collecting and/or discharging residual water, the air humidification device 4 may be equipped with a pan 24, which, in the example shown, has a fill level sensor 26 and a water outflow 40. In the exemplary embodiment shown, a valve (not separately provided with a reference sign) is provided in the water outflow 40 such that the fill level in the pan 24 increases when the valve is closed, said valve being opened in the presence of a sensor signal of the sensor 26 so that the residual water can flow out. In one modification (not shown separately), the water outflow 40 may also be designed in the form of a constantly open overflow, with the result that the valve in the water outflow 40 and also the fill level sensor 26 may be dispensed with. However, the fill level sensor 26 may also be used with an overflow in order, possibly, to be able to detect a blockage of the water outflow 40 if the water level in the pan 24 increases.

Arranged on the exit side of the air humidification device 4, that is to say preferably in a manner arranged downstream of the separating system 18, is at least one sensor apparatus 42. Said exit-side sensor apparatus 42 may have a moisture sensor and/or a temperature sensor. Alternatively or additionally, it is possible for at least one second sensor apparatus 44 to be arranged on the entry side of the air humidification device 4, which second sensor apparatus preferably has a moisture sensor. With the aid of these sensor apparatuses 42, 44, the moisture content and/or the temperature in the air stream can be detected. The sensor apparatuses 42, 44 are coupled to the control apparatus 48.

A pressure sensor 46 for detecting the water pressure is provided between the pump 34 and the nozzles 14. This at least one pressure sensor 46 is coupled to the control apparatus 48.

The one or more sensor apparatuses 42, 44, coupled to the control apparatus 48, and/or the pressure sensor 46 transmit(s) signals to the control apparatus 48, wherein it is possible for the signals to be processed by the control apparatus 48 and used for the regulation of the air humidification device 4. For regulating the air humidification device 4, the control apparatus 48 transmits adjustment signals to actuators of the air humidification device 4, for example to the pump 34, an adjustment apparatus 80 (see FIGS. 9 and 10) for the nozzles 14 and/or one or more valve apparatuses 36.

For regulating the air humidification device 4, it is preferably possible for use to be made of measurement values of the humidity sensor of the exit-side sensor apparatus 42. Since adiabatic cooling is realized in the reaction chamber 6, it may be expedient if, additionally, use is made of measurement values of a temperature sensor of the exit-side sensor apparatus 42. The regulation accuracy can be further improved if, additionally, use is made of measurement values of the moisture sensor of the inlet-side sensor apparatus 44.

The control apparatus 48 may be provided with a user interface and preferably has display and operator control elements.

The liquid stream flowing into the nozzle system 8, in particular a water stream, can be set by means of the control apparatus 48. Preferably here, the liquid atomization is adapted to the humidity requirements, that is to say to the requirements for the conditioned air, by clocked operation of the individual nozzle bars. The three nozzle bars 28 of the air humidification device 4 are able to be activated separately in accordance with the exemplary embodiment shown in FIG. 1.

The activation of the nozzle bars 28 can be realized for example in accordance with the procedure described below or a modification thereof: In a manner dependent on the humidity requirements for the conditioning of the air stream, in the case of an increasing humidity requirement, firstly a first nozzle bar 28, for example the highest nozzle bar 28, is activated and is subjected to pulse width modulation at a ratio of 0 to 100%, with a minimum pulse width taken into consideration. If the humidification capacity with permanent valve opening for the first nozzle bar 28 is insufficient, then a second nozzle bar 28, for example the nozzle bar 28 situated below the first one, is activated and is subjected to pulse width modulation in an identical or similar manner. Further nozzle bars 28 are activated in accordance with this principle until all the nozzle bars 28 are completely open and the maximum humidification capacity of the air humidification device 4 has thereby been set. In the case of a decreasing humidity requirement, the individual nozzle bars 28 are, in an analogous procedure, deactivated in succession in reverse order or deactivated simultaneously.

The pressure, provided by the pump 34, of the liquid can be detected by means of the pressure sensor 46 and, for example via the rotational speed of the pump 34, set to a predefined value. In the case of part load, it is possible under some circumstances that the delivery rate of the pump 34 is so low that, even at a minimum rotational speed of the pump 34, the predefined pressure is exceeded. For such a case, a bypass duct (not illustrated in more detail) having an activatable proportional valve may be provided, with the aid of which the pressure can be adjusted in a regulated manner to the predefined value. Even if all the valve apparatuses 36 are closed, it is possible for pressure to be released via the bypass duct in this manner. Additionally, for the purpose of preventing pressure overloading in the event of a defect of the proportional valve, it is possible for a further bypass duct having an overflow valve to be provided. In a simplified configuration without an activatable proportional valve, the overflow valve may also be used for pressure regulation, wherein the pump 34 can be operated with rotational speed regulation or at constant rotational speed.

FIG. 2 shows, in a perspective view, a part of a nozzle assembly 30 with a nozzle 14 which is arranged on a section of a distributing line 50 of the nozzle assembly 30. Such a distributing line 50 may be equipped with multiple further nozzles 14 (not illustrated in more detail here). In the example shown, the nozzle 14 is arranged in a tube piece 52. The head 58 of the nozzle 14 projects from the tube piece 52 and has an outlet opening 56. The tube piece 52, for example a sleeve, is connected to the distributing line 50, wherein the tube piece 52 may expediently be welded to the distributing line 50. In the example shown, the tube piece 52 has an outer thread 54, with the aid of which an attachment part can be fastened to the tube piece 52. The nozzle 14 is expediently designed in the form of a swirl nozzle and may have a swirl body (not illustrated in more detail), which is arranged in the interior of the nozzle 14. The tube piece 52 may have an inner thread (not illustrated in more detail), into which the nozzle 14 can be screwed. In the case of a swirl nozzle or a simplex nozzle, the liquid to be atomized passes through the outlet opening 56 of the nozzle 14 preferably as a rotating liquid film ring and subsequently forms a liquid film cone, which, owing to its instability, disintegrates into small liquid droplets.

FIG. 3 shows, in a perspective view, a turbulator apparatus 60 for influencing the air flow at a nozzle 14, on the head 58 of which an outlet opening 56 for water is provided. The turbulator apparatus 60 has at least one fixed wing 62 and may be designed for example in the form of a sheet metal part. In the example shown, the turbulator apparatus 60 has multiple wings 62. Said wings 62 serve as turbulators for the air flow and are arranged upstream of the nozzle 14, in particular the outlet opening 56 of the nozzle 14, in the air stream. The turbulator apparatus 60 may expediently be screwed onto an outer thread 54 of the tube piece 52 accommodating the nozzle 14 (see FIG. 2). Here, the turbulator apparatus 60 is designed and arranged such that the wings 62 have a swirl direction which counteracts unscrewing of the turbulator apparatus 60 from the outer thread 54.

FIG. 4 shows, in a simplified sectional view, a distributing line 50 of a nozzle assembly 30 with a tube piece 52 which carries a nozzle 14. In the example shown, the nozzle assembly is equipped with turbulators. For this purpose, it is possible, as illustrated in FIG. 4, for the pipe piece 52 to be equipped with a turbulator apparatus 60 which has multiple turbulators which are designed in the form of wings 62. A nozzle 14, in the head 58 of which an outlet opening 56 for water is provided, is screwed in the tube piece 52. Provided between the nozzle 14 and the tube piece 52 is a sealing apparatus 64, which can preferably be designed in the form of an O-ring.

The nozzle 14 shown in FIG. 4 is designed in the form of a simplex nozzle. This simplex nozzle is equipped with at least one filter apparatus, wherein, in the example shown, the nozzle 14 has a primary filter 68 and a secondary filter (which is not illustrated in more detail). The primary filter 68 comprises a so-called drop stop, as is known per se. In this way, the function of a kind of overpressure valve is achieved, such that, below a threshold pressure, no water can emerge. Preferably, the at least one filter apparatus is integrated into the nozzle 14.

A swirl body (not illustrated in more detail) may be provided in the interior of the simplex nozzle in a manner arranged downstream of the at least one filter apparatus, said swirl body being provided on its side which faces the outlet opening 56 of the nozzle 14 with one or more ducts 66 for the liquid. The water is able to pass to the outlet opening 56 of the nozzle 14 through the at least one duct 66.

In one exemplary configuration for an industrial application, the tube piece 52 may have a diameter of approximately 2 to 3 cm, wherein the distributing line 50 of the nozzle assembly 30 may have a diameter of approximately 5 cm, and wherein the turbulator apparatus 60 may generally have an outer diameter of up to 30 cm.

FIGS. 5 to 7 show side views of a nozzle 14 for atomizing water in a highly simplified basic illustration, wherein the nozzle 14 is arranged on a nozzle assembly 30. The water emerging from the nozzle 14 forms a spray cone 70, 74 or 78, wherein the spray cones 70, 74 and 78 shown in FIGS. 5 to 7 each differ from one another. A measure for the size of such a spray cone 70, 74 or 78 is for example the opening angle thereof.

FIG. 5 illustrates, by way of example, the spray cone 70 of the nozzle 14 if air does not flow around the latter.

FIG. 6 shows the nozzle 14 in an air flow 72, wherein the spray direction of the nozzle 14 is oriented in the direction of the main flow direction of the air flow 72. Due to the air flow 72, the opening angle of the spray cone 74 of the nozzle 14 shown in FIG. 6 is less than the opening angle of the spray cone 70 of the nozzle 14 without air flow as per FIG. 5.

FIG. 7 shows the nozzle 14 in an air flow 76, wherein provision is made of a turbulator apparatus 60 for influencing the air flow 76. In FIG. 7, for greater clarity, the wings of the turbulator apparatus 60, which wings form the turbulators, are not provided with reference signs. Due to the effect of the turbulator apparatus 60 on the air flow 76, the opening angle of the spray cone 78 as per FIG. 7 is greater than the opening angle of the spray cone 74 as per FIG. 6. In a corresponding configuration of the turbulator apparatus 60, the air flow 76 can be influenced such that the opening angle of the spray cone as per FIG. 7 is greater than the opening angle of the spray cone 70 for a nozzle 14 without air flow as per FIG. 5. In the example shown, the turbulator apparatus 60 is arranged directly upstream of the nozzle 14 in the air flow 76.

FIGS. 8 and 9 show, in a simplified basic illustration, the nozzle assembly 30 of an air humidification device 4. The nozzle assembly 30 has multiple nozzle bars 28, which, in the examples shown, each extend horizontally in the reaction chamber 6 of the air humidification device 4 and are arranged parallel to one another. It is possible for the nozzle bars 28 to also be provided in a differently formed arrangement in the reaction chamber 6. In this regard, for example, the nozzle bars 28 may extend vertically or else diagonally in the reaction chamber 6. Preferably, the nozzles are arranged distributed at least virtually over the entire cross section of the reaction chamber 6.

In the exemplary embodiments as per FIGS. 8 and 9, in each case one distributing line 50 a, 50 b or 50 c is provided for each nozzle bar 28. Each distributing line 50 a, 50 b, 50 c carries multiple nozzles 14, which, for the sake of greater clarity, are provided with reference signs only in part. The nozzles 14 may be designed such that, and/or operated such that, the degrees of atomization of nozzles 14 which are arranged on different distributing lines 50 a, 50 b, 50 c differ from one another. In this regard, for example, the nozzles 14 arranged on the lower distributing line 50 c may atomize the liquid more finely than the nozzles 14 of the middle distributing line 50 b, wherein the nozzles 14 of the upper distributing line 50 c atomize the liquid even more coarsely than the nozzles 14 arranged on the middle distributing line 50 b. In an alternative configuration, it is also possible for all the nozzles 14 of the nozzle assembly 30 to atomize the liquid in a manner which is at least virtually the same.

The angle of inclination of the nozzles 14 may be set during the mounting of the nozzle assembly 30. In an alternative configuration, the angle of inclination of the nozzles 14 may be varied by means of one or more actuators. As per FIGS. 8 and 9, it is possible to provide as an actuator for setting the orientation of the nozzles 14 an adjustment apparatus 80, which may be designed for example in the form of a motor, for example in the form of an electric motor, or in the form of some other drive unit, for example in the form of an adjustment cylinder. By means of the adjustment apparatus 80, it is possible for example for one or more distributing lines 50 a, 50 b, 50 c to be rotated together or independently of one another, whereby the orientation of the nozzles 14 arranged on the distributing lines 50 a, 50 b and 50 c is changed. If a distributing line 50 a, 50 b, 50 c is rotated about its axis, then at the same time the nozzles 14 arranged on the distributing line 50 a, 50 b, 50 c are pivoted. Consequently, by means of the adjustment apparatus 80, the angle of inclination of one or more groups of nozzles 14 can be set. Preferably, the adjustment apparatus 80, as an actuator, is coupled to the control apparatus 48 (see FIG. 1).

In the example shown in FIG. 8, the nozzles 14 of all the distributing lines 50 a, 50 b, 50 c have the same orientation. As per the example shown, the nozzles 14 of all the distributing lines 50 a, 50 b, 50 c are arranged horizontally and parallel to one another. It is also possible for the angles of inclination of the nozzles 14 on different distributing lines 50 a, 50 b, 50 c to differ from one another. In the example shown in FIG. 9, the nozzles 14 of the lowermost distributing line 50 c for example have an angle of inclination of approximately 30° to the horizontal, while the nozzles 14 of the remaining distributing lines 50 a, 50 b are oriented horizontally.

FIG. 10 shows, in a perspective and simplified basic illustration, a nozzle assembly 30 with nozzles 14 of a nozzle bar 28 that are arranged along a section of a distributing line 50. The nozzles 14 arranged along the distributing line 50 have different orientations, wherein, in the example shown, nozzles 14 which follow one another along the distributing line 50 each have a different orientation. Here, as per the example shown, adjacently arranged nozzles 14 have, in each case alternately, a positive angle of inclination and a negative angle of inclination to the horizontal, wherein the difference in the angle of inclination between adjacent nozzles 14 is approximately 60° as per FIG. 10. In one advantageous configuration, it is possible for multiple nozzle bars 28 with alternately differently oriented nozzles 14, illustrated by way of example in FIG. 10, to be provided in the reaction chamber (see FIG. 1) of an air humidification device 4. These nozzle bars 28 may in turn be designed and arranged such that a kind of two-dimensional nozzle matrix having nozzles 14 which, in both dimensions of the matrix, are in each case alternately differently oriented is formed.

Depending on the application and place of use of the air humidification device 4, the reaction chamber 6 (see FIG. 1) may have a cross-sectional area of up to 50 m² and more. Typically, the cross-sectional area of the reaction chamber 6 is up to approximately 4 m² in a room-air application and between approximately 4 m² and approximately 50 m² in an industrial applications. In one exemplary configuration for an industrial application, it is possible to provide, per meter of a nozzle bar 28, one nozzle 14 on the nozzle bar 28.

A concept on which the invention is based can be summarized as follows: The present invention relates to an apparatus for conditioning room and/or process air, having a nozzle system 8 which has multiple nozzles 14, which are arranged in one or more nozzle bars 28 and serve for atomizing liquid, and having at least one pump 34, by means of which the liquid to be atomized is subjected to pressure, wherein the nozzles 14 are designed in the form of swirl nozzles, and/or wherein the pump 34 subjects the liquid to be atomized to a pressure of between 3 and 50 bar. According to the invention, the liquid, in particular water, can be particularly finely atomized and a good degree of evaporation can be attained, whereby the quantity of water lost is reduced too. The apparatus according to the invention is distinguished by low susceptibility to faults, a long service life of the pump 34 and low maintenance effort.

FIG. 11 shows a treatment facility 96 having a treatment booth 98 of an installation, denoted overall by 100, for the treatment of workpieces 102. In this exemplary embodiment, the air stream to be treated is at least partially waste air 104 that is formed during the work process which proceeds in the treatment facility 96.

Such a treatment facility 96 may be used for example in the automotive industry in installations for the treatment of vehicle bodies and, there, in particular at treatment booths in which coated vehicle bodies are treated in the context of a painting process. These include in particular painting booths, but also for example evaporation booths, cooling booths and dryers, with in each case one treatment tunnel. Therefore, as an example of workpieces 102, in each case vehicle bodies are shown here. The workpieces 102 may however also be other workpieces and, in particular, attachment or structural parts of vehicle bodies, such as bumpers, side mirrors or the like. Smaller workpieces 102 may, if appropriate, be arranged on a workpiece carrier (not shown separately).

The above-discussed air humidification device 4 is part of a conditioning device 106 in which the air stream, which contains the waste air 104, is conditioned to form conditioned process air 108.

The treatment booth 98 of the treatment facility 96 delimits a working space in the form of a treatment tunnel 110, which has a tunnel entry and a tunnel exit through which the workpieces 102 to be treated are conveyed by means of a conveying system 112, as is known per se and which does not need to be discussed in further detail.

The treatment tunnel 110 has an air outlet 114 and an air inlet 116, between which the conditioning apparatus 106 is arranged such that it is possible for waste air 104 to be drawn in from the treatment tunnel 110, conveyed through the conditioning apparatus 106 and, after conditioning has been carried out, supplied to the treatment tunnel 110 again as process air 108 in a circulating manner. The returned process air 108 is, in a manner known per se, guided via nozzles (not illustrated separately) to the workpieces to be treated.

In this way, it is possible to maintain in the treatment tunnel 110 the temperature required for effective treatment and treatment conditions. In one modification (not shown separately), the treatment tunnel 110 may also be subdivided into multiple tunnel sections, each of which has a separate air outlet and air inlet, which are connected to the conditioning apparatus 106. If appropriate, it is also possible for each tunnel section present to be assigned a dedicated conditioning device 106, such that, in each tunnel section, different temperatures and treatment conditions can be set, as is most favorable for the treatment process in each case.

The conditioning apparatus 106 defines a flow path for the air flow with multiple conditioning stages 118. In the exemplary embodiment discussed here, six conditioning stages 118 are present by way of example, which comprise a pre-heating device 118.1, a first filter device 118.2, a cooling device 118.3, a post-heating device 118.4, an air humidification stage 118.5 in the form of the air humidification device 4 and a second filter device 118.6. The air stream with the waste air 104 is conveyed through the conditioning stages 118 with the aid of a blower 120.

A supply line 122 connects the air outlet 114 of the treatment tunnel 110 to the conditioning apparatus 106. A valve 124 is arranged in the supply line 122 such that the volume flow of the waste air 16 to the entry connection unit 36 can be set.

The conditioning apparatus 106 is also connected to a fresh-air line 126, via which fresh air can be introduced the air stream. The volume flow of the fresh air to the conditioning apparatus 106 can be set by means of a valve 128. The conditioning process for the waste air 104 from the treatment tunnel 110 therefore also includes the admixture of a fraction of an admixing gas, in the present case a fraction of fresh air. Therefore, generally, a mixture of the waste air 104 and fresh air 56 always flows through the conditioning device 106.

On the exit side of the conditioning apparatus 10, a process-air line 130 having a valve 132 leads to the air inlet 116 of the treatment facility 96, with the result that the flow circuit is closed. 

What is claimed is:
 1. An apparatus for humidifying an air stream, comprising: (a) a nozzle system which has multiple nozzles for atomizing liquid, (b) at least one pump, by means of which the liquid to be atomized is subjected to pressure, wherein (c) the multiple nozzles are designed in the form of swirl nozzles which are arranged in one or more nozzle bars, and/or (d) the at least one pump is designed such that the pressure of the liquid to be atomized is between 3 and 50 bar.
 2. The apparatus as claimed in claim 1, wherein the nozzles are designed in the form of simplex nozzles.
 3. The apparatus as claimed in claim 1, wherein the multiple nozzles each have at least one filter apparatus, which is integrated into the nozzle.
 4. The apparatus as claimed in claim 1, wherein the at least one pump is designed in the form of a centrifugal pump.
 5. The apparatus as claimed in claim 1, wherein the at least one pump is designed in the form of a reciprocating-piston pump.
 6. The apparatus as claimed in claim 1, wherein the pressure provided by the at least one pump is between 20 and 50 bar.
 7. The apparatus as claimed in claim 1, wherein the pressure provided by the at least one pump is between 3 and 30 bar.
 8. The apparatus as claimed in claim 1, wherein the multiple nozzles are arranged on a nozzle assembly which is equipped with turbulators.
 9. The apparatus as claimed in claim 8, wherein the turbulators are arranged upstream of the multiple nozzles in the air stream.
 10. The apparatus as claimed in claim 1, further comprising at least one adjustment apparatus for setting the orientation of one or more of the multiple nozzles of the nozzle system.
 11. The apparatus as claimed in claim 1, wherein nozzles from the multiple nozzles of a first nozzle bar have a degree of atomization which differs from the degree of atomization of nozzles from the multiple nozzles of a second nozzle bar.
 12. The apparatus as claimed in claim 1, wherein nozzles of the multiple nozzles which follow one another along a nozzle bar each have a different orientation.
 13. The apparatus as claimed in claim 1, further comprising a control apparatus, the control apparatus regulating the supply of liquid to the multiple nozzles.
 14. The apparatus as claimed in claim 13, wherein multiple nozzle bars are each coupled to a valve apparatus, by means of which the supply of liquid to the corresponding nozzle bar is able to be regulated.
 15. The apparatus as claimed in claim 13, wherein provision is made of at least one sensor which is coupled to the control apparatus and which serves for measuring humidity in the air stream.
 16. An installation for the treatment of workpieces comprising: a conditioning apparatus for waste air, wherein the conditioning apparatus comprises an apparatus for humidifying an air stream as claimed in claim
 1. 17. The apparatus as claimed in claim 1, wherein the pressure provided by the at least one pump is between 8 and 25 bar. 